The Solution Chemistry of Cu²⁺–tren Complexes Revisited: Exploring the Role of Species That Are Not Trigonal Bipyramidal

Abstract

International audienc

Equilibrium and kinetics studies on bibrachial lariat aza-crown/Cu(II) systems reveal different behavior associated with small changes in the structure

“…The kinetic data in the present work indicate that the previously detected structural reorganization of Cu 2+ between different pentacoordinate geometries [30,[49][50][51] are also possible with more complicated receptors. Moreover, the different behavior detected for the L1 and L2 ligands indicates that subtle changes in the nature of the ligand can lead to drastic changes in the chemical behavior.…”

“…In previous papers we have found that the combination of theoretical studies with experimental information is very useful to understand structural reorganizations between sp and tbp geometries in macrocyclic copper complexes [30,[49][50][51]. For that reason, and despite the very complex nature of the present systems hinders a detailed theoretical study, we decided to carry out some DFT and TD-DFT calculations aimed to analyze the possible coordination modes of Cu 2+ coordinated to L1 and L2, as well as obtaining the corresponding calculated spectra in order to compare them with the experimental results.…”

“…For that reason, and despite the very complex nature of the present systems hinders a detailed theoretical study, we decided to carry out some DFT and TD-DFT calculations aimed to analyze the possible coordination modes of Cu 2+ coordinated to L1 and L2, as well as obtaining the corresponding calculated spectra in order to compare them with the experimental results. To simplify the calculations, and considering that previous work [30,50] indicated that the external aromatic rings in these species do not participate in the coordination to copper centers, those aromatic rings were substituted in the model system by methyl groups to avoid conformational issues and reduce computational time. Initially, the efforts were focused on the location of all the different coordination modes that the methylated generic ligand L offers to one Cu 2+ ion.…”

Synthesis, Structures, and Solution Dynamics of Titanium and Zirconium Complexes Carrying a Bis(indolyl) and Two Diethylamido Ligands

“…The coordination geometries of the five-coordinated complexes can be discussed using the τ-value, 21 which can be calculated by τ = (α − β)/60, where α and β denominate the largest and the second-largest angles around the metal center, respectively. Complexes with τ = 0 adopt an ideal square-pyramidal geometry, while those with τ = 1 adopt a nondistorted trigonal-bipyramidal geometry.…”

Anion‐Directed Copper(II) Metallocages, Coordination Chain, and Complex Double Salt: Structures, Magnetic Properties, EPR Spectra, and Density Functional Study

“…Metalloprism 6 shows four‐line hyperfine structure at 77 K, corresponding to the Δ m s =1 transition. Neither the Δ m s =2 transition nor complete delocalization of the unpaired electron was detected, and hence this is a case of noncommunicating copper(II) dimers in a square‐pyramidal environment ( g || >2.1> g ⊥ >2.00, and A || =148×10 −4 cm −1 ; Supporting Information, Figure S10) …”